diff --git a/frontend/app/(main)/admin/files/components/storage-config-tab.tsx b/frontend/app/(main)/admin/files/components/storage-config-tab.tsx
index 1b31c613..b6fdd5a0 100644
--- a/frontend/app/(main)/admin/files/components/storage-config-tab.tsx
+++ b/frontend/app/(main)/admin/files/components/storage-config-tab.tsx
@@ -149,13 +149,8 @@ export function StorageConfigTab() {
 
   const saveMutation = useMutation({
     mutationFn: async (value: StorageConfig) => {
-      const activeDriver = query.data?.config.driver || value.driver
-      const valueToSave = {
-        ...value,
-        driver: activeDriver,
-      }
       await services.adminSystemConfig.updateSystemConfig(storageConfigKey, {
-        value: JSON.stringify(valueToSave),
+        value: JSON.stringify(value),
       })
     },
     onSuccess: () => {
diff --git a/internal/apps/admin/system_config/routers.go b/internal/apps/admin/system_config/routers.go
index ed92c7a9..6fdbc21f 100644
--- a/internal/apps/admin/system_config/routers.go
+++ b/internal/apps/admin/system_config/routers.go
@@ -307,19 +307,12 @@ func validateAndMergeStorageConfig(ctx context.Context, value string, currentCon
 
 	// 合并被掩码屏蔽的敏感信息，获取完整的真实配置
 	targetCfg := storage.MergeMaskedSecrets(newCfg, currentCfg)
-
-	// 校验配置参数是否合法
-	if err := storage.ValidateConfig(targetCfg); err != nil {
-		return "", fmt.Errorf("验证存储配置参数失败: %w", err)
+	if err := validateMergedStorageConfig(ctx, currentCfg, newCfg, targetCfg); err != nil {
+		return "", err
 	}
-
-	// 进行连通性测试验证，如果测试失败则拒绝保存
-	testBackend, err := storage.NewBackend(ctx, targetCfg, targetCfg.Driver)
-	if err != nil {
-		return "", fmt.Errorf("初始化测试存储实例失败: %w", err)
-	}
-	if err := testBackend.Test(ctx); err != nil {
-		return "", fmt.Errorf("存储连通性测试失败: %w", err)
+	if newCfg.Driver != "" && newCfg.Driver != currentCfg.Driver {
+		// 切换存储类型时仅暂存目标后端参数，活动 driver 由迁移任务正式切换。
+		targetCfg.Driver = currentCfg.Driver
 	}
 
 	// 序列化为最终保存的真实明文配置，防止保存屏蔽的 ****** 字符
@@ -330,3 +323,35 @@ func validateAndMergeStorageConfig(ctx context.Context, value string, currentCon
 
 	return string(unmaskedVal), nil
 }
+
+func validateMergedStorageConfig(ctx context.Context, currentCfg, newCfg, targetCfg storage.Config) error {
+	if newCfg.Driver != "" && newCfg.Driver != currentCfg.Driver {
+		if err := validateDriverConfig(targetCfg, newCfg.Driver); err != nil {
+			return fmt.Errorf("验证目标存储配置参数失败: %w", err)
+		}
+		pendingCfg := targetCfg
+		pendingCfg.Driver = newCfg.Driver
+		return testStorageBackend(ctx, pendingCfg, newCfg.Driver)
+	}
+
+	if err := storage.ValidateConfig(targetCfg); err != nil {
+		return fmt.Errorf("验证存储配置参数失败: %w", err)
+	}
+	return testStorageBackend(ctx, targetCfg, targetCfg.Driver)
+}
+
+func validateDriverConfig(cfg storage.Config, driver storage.Driver) error {
+	cfg.Driver = driver
+	return storage.ValidateConfig(cfg)
+}
+
+func testStorageBackend(ctx context.Context, cfg storage.Config, driver storage.Driver) error {
+	testBackend, err := storage.NewBackend(ctx, cfg, driver)
+	if err != nil {
+		return fmt.Errorf("初始化测试存储实例失败: %w", err)
+	}
+	if err := testBackend.Test(ctx); err != nil {
+		return fmt.Errorf("存储连通性测试失败: %w", err)
+	}
+	return nil
+}
diff --git a/internal/apps/admin/system_config/routers_test.go b/internal/apps/admin/system_config/routers_test.go
index fd423736..b6e9270c 100644
--- a/internal/apps/admin/system_config/routers_test.go
+++ b/internal/apps/admin/system_config/routers_test.go
@@ -440,4 +440,57 @@ func TestUpdateStorageConfigValidation(t *testing.T) {
 			t.Errorf("expected 400 Bad Request, got %d. Body: %s", w.Code, w.Body.String())
 		}
 	})
+
+	t.Run("stage local config while active s3 is unreachable", func(t *testing.T) {
+		activeCfg := storage.DefaultConfig()
+		activeCfg.Driver = storage.DriverS3
+		activeCfg.S3.Endpoint = "http://127.0.0.1:9999"
+		activeCfg.S3.Region = "us-east-1"
+		activeCfg.S3.Bucket = "wavelet"
+		activeCfg.S3.AccessKeyID = "test"
+		activeCfg.S3.SecretAccessKey = "test"
+		activeBytes, _ := json.Marshal(activeCfg)
+		seedCfg := model.SystemConfig{
+			Key:   "storage_config",
+			Value: string(activeBytes),
+			Type:  "system",
+		}
+		if err := dbConn.Where("key = ?", "storage_config").
+			Assign(map[string]any{"value": seedCfg.Value, "type": seedCfg.Type}).
+			FirstOrCreate(&seedCfg).Error; err != nil {
+			t.Fatalf("seed active storage config failed: %v", err)
+		}
+
+		tempDir := t.TempDir()
+		stagedCfg := activeCfg
+		stagedCfg.Driver = storage.DriverLocal
+		stagedCfg.Local.Root = tempDir
+
+		cfgBytes, _ := json.Marshal(stagedCfg)
+		payload := UpdateSystemConfigRequest{Value: string(cfgBytes)}
+		body, _ := json.Marshal(payload)
+		req, _ := http.NewRequest("PUT", "/api/v1/admin/system-configs/storage_config", bytes.NewBuffer(body))
+		req.Header.Set("Content-Type", "application/json")
+		w := httptest.NewRecorder()
+		router.ServeHTTP(w, req)
+
+		if w.Code != http.StatusOK {
+			t.Fatalf("expected 200 OK, got %d. Body: %s", w.Code, w.Body.String())
+		}
+
+		var dbCfg model.SystemConfig
+		if err := dbConn.Where("key = ?", "storage_config").First(&dbCfg).Error; err != nil {
+			t.Fatalf("load saved storage config failed: %v", err)
+		}
+		var savedCfg storage.Config
+		if err := json.Unmarshal([]byte(dbCfg.Value), &savedCfg); err != nil {
+			t.Fatalf("parse saved storage config failed: %v", err)
+		}
+		if savedCfg.Driver != storage.DriverS3 {
+			t.Fatalf("active driver = %q, want %q until migration completes", savedCfg.Driver, storage.DriverS3)
+		}
+		if savedCfg.Local.Root != tempDir {
+			t.Fatalf("staged local root = %q, want %q", savedCfg.Local.Root, tempDir)
+		}
+	})
 }